That’s a fair concern. After all, the sun still sets every evening and winds blow sporadically in most locations. If you don’t want your lights getting brighter and dimmer, you need something to smooth out the fluctuations. That something is energy storage.
Coal, nuclear and natural gas fired generating plants don’t need storage. The energy storage is built into the fuel. There is also a short-term energy reserve in the steam boilers that only heat up and cool down so fast. Not so with windmills and solar panels. They have no fuel. They extract energy that is directed at them and only while they have access to that energy source.
At first glance, this appears to be a show-stopper for alternative energy. But it’s really not that bad. The sun doesn’t shine at night, but most of us don’t either. When it gets dark, we go home and shut down offices, factories, schools and stores. The biggest energy demand is during the day. That’s also the biggest demand for air conditioning, because the same sun that makes it bright outside and lets solar panels tap it for electricity also heats everything up. The wind doesn’t blow all the time either, but it’s usually blowing somewhere. That’s the value of an energy grid. Sources that contribute energy feed the grid and users that need energy tap it.
Some of the difference between supply and demand can be handled by base load generators. These are things like nuclear power, geothermal, and natural gas generators that can produce at a steady rate regardless of what’s going on with the weather.
But really making good use of clean energy sources that may generate too much power some times and not enough at other times requires storage. Users that are so far “off the grid” that it’s too expensive to string wires to their cabins often use lead acid storage batteries. Wind and solar generators charge up the batteries when they can. The user draws power from the batteries as needed.
Batteries are a good idea, but the automobile style lead acid batteries have some limitations. You need a lot of them to store much energy, so they take up a lot of room. They emit nasty gasses that need to be vented. Battery life is also more limited than we would like.
Nickel-metal hydride batteries are more energy dense and are the battery of choice for today’s hybrid cars. Lithium ion batteries can store even more energy per cubic foot and are the batteries chosen for plug-in hybrids and electric cars. They’re a bit pricey when you get to the capacities needed to run a home or business, but that’s soon to change. As Li-ion batteries get into mass production in vehicle sizes, the prices will plummet. How soon before they’re reasonably priced for fixed location battery backup?
What I’m talking about is a unit about the size of a furnace that will have a battery, inverter and control circuitry suitable to run the entire electrical load of a residence or small business. Power outages will be a thing of the past. Feed one of these from solar panels on the roof or a wind generator out back and you can go off the grid any time you want and avoid paying the electric company for power. Or, better yet, let them pay you for power.
Rather than round up all the batteries and put them at the generating station, why not distribute both generation and storage of electrical power? The grid still makes sense for sharing power among users. Those who are power rich can sell their excess capacity. Those who have demanding needs, like steel mills, street lights, and buildings without generation or storage will just pay the electric bill like today. The difference is that most of the generating sources can be green. The system will be more robust because a million small resources aren’t as likely to go out of service at the same time as one or two large generators.
The availability of reasonably priced generation and storage may give rise to a new era of energy entrepreneurs. Savvy producers will want to sell as much as possible during the heavy-demand daylight hours to get the best price possible. At night, they could even draw off the grid at lower prices to run their own lights and recharge their batteries. How about the family energy farm? A field of windmills and solar roof panels augmented by fields of corn for ethanol between the wind generator towers may offer the kind of income that makes independent rural life really attractive again. Factories and warehouses with large flat roofs offer ready real estate to load up with angled solar panels to eliminate power bills and become a revenue source. Ever shrinking payback periods are making this type of investment more and more practical.
Alternative energy is a key piece in putting the brakes on climate change before our environment degenerates into something that we’ll really hate dealing with. If you share our interest in this important topic, you’ll be interested in the huge collection of articles being posted on blogs worldwide as part of Blog Action Day 2009: Climate Change. The official event is October 15, but we’re participating all week with articles on this subject. Come back tomorrow for our feature on banishing power vampires that suck your “juice.” Say, isn’t Halloween just around the corner?
